Slip regulator



April 14, 1925. 1,533,253

. H. A. LEWIS SLIP REGULATOR Filed Aug. 2e, 1922 4 sheets-sheet 1 Fig. 1.

wlTNEssEs; INVENToR f# Harry H.Lew|s. l

` fwn/Afef? BY I v ATTORNEY i April 14,., 1925. v 1,533,253

' H. A. LEWIS SLIP REGULATOR Filed Aug. 28. 1922 v 4 sheets-sheet 2 Pig; Z..

WITNEssEs; f i VlNvi-:NTOR

(707% v H Lewis.

' 2 TTORNEY Aprily 14. 1925.`

H. A. LENS l SLIP REGULATOR Filed Aug. 28, 1922 4 Sheets-Sheet wwwa Hamg RLew.

wVrNEsss-:s': fr# M,

Api'il 14, 192.5. 1,533,253

H. A. LEWIS sLI'P REGULATOR Filed Angles, 1922 4 sheets-sneet 4 LLSI 'Uas/Q u* 3 AT'ToRNEY Slip Regulators, ofwliieh the following is a .f

Patented Apr. 14, 1925.

.; g-U'Nsiren STATES PATENT. grins.

HAR-RY A. `LIESTIS, OFNO'RRSTOWN,PENNSYLVANA, ASSIGNOR T0 WESTNGHQUSE ELECTRC &MANUFACTUR1NG COMPANYA .CGRPORATION 0F PENNSYLVANIA.

SLIP REGULATOR.

4'Application filed .August 28,1922. l#Serial No. 584,643.

To all fio/1.0122, /e't may conce/1%:

. Be it-.known .that I, Hai-nir A. Lewis, a citizen ofthe United States, and a `resident .ery and State of lPennsylvania, have1 invented a new and. useful. Improvement in specication.

My invention'relates to slip regulators or liquid rheostats, and itl has particular relaltioii to certain. improved structural features Vthereof whereby a highly efficient `and effective slip regulator or thelike is provided.

` One object of myinvention is tov provide a slip regulator or liquidrlieostati wherein Aeach stationaryelectrode isi-located insub- `stantially vertical. alineinentwithtlie movable-electrode and issupported by a plurality of rods or the like thatextend upwardly on .opposite sides offtlie movable electrode.

vAnother obj ect of :my invention is to provide Van electrodey arrangement ofzthecharacter just set forth wherein .thenietallic V,snpporting.;` or suspending `rods are covered by yunitary .insulatingmeans, inforder that- ,the path of.` the electric :current inthe rheostat may be substantially coniined to the snaeeibetweenthe inovabl'eelectrode and the mainv working' member or plate of the stationary electrode.

A Af rther object of my .invention Ais to provide novel construction whereby-.the above-described stationary electrodes may be satisfactorily supponted. by, andiiinsu'- lated from, the rheostat tank withont iiiterfering with the assembly'or. operation of `the, other necessary; parts of the jslip regulator.

Still another object of my invention is to .pian/'idc a tank or container for a-body of oleztrolyte in which a plurality of sets. of co-opei'ating` stationary and Emovable electrodes are respectively enclosed by-{cyliiidrical members, such as .thewell-known sewer tiles, to Yseparate the electrodes-correi-pondingl to .theaespectivephases of -the electric circuitand, at the same' time, to eliminate thefpessibility of lossi or leakage ofthe electrolyte from the cylindrical meinbers, inasmuch as the electrolyteis piiovided both wit-hin and surrounding-the sewer tiles.

Another `object of. my intention is 'to provide, in conjunction ywith the-familiar torque motorl for yoperating the movable electrodes, of Norristown, in the county ofli/lontgoin- .f

-i'etaided in :case a 'sudden load is imposed upon the main. motor that is regulated by theV slip regulator and also, on the other hand, the ytorque motoris assisted in causing` theelectrodes to come together more quickly and thus facilitate the return of the main -motor to :normal speed.

A further object of my. invention is to provide a Vnovel type of cooling` tank which will eifectively-perform its desiredfunction without interference with the normal action of the electrolyte .and be practically portable, being readily removed for `repairs or replacement. ""OtlierobJects of myiinvention will berome .-evidentfrom the :following description, taken in=conjnnction .with the .accompanying drawings, whereinvFigui-esl isa view, iii front elevation, of a liquid rlieostat constructed vand `arranged in accordance with my present invention;

Fig. 2 is a view, in side-elevation, of the structurethat is-showii in-flig. l;

Fig. 3 is a plan view, with certain parts gciitx away, for the sake of clearn'ess, ofiny slip regulator; and

Figs. 4 and .f5 .are views, in elevation and in plan, respectively, of the coolingtanks Vthat are .employed in fconnection with the liquid .frlie'ostat illustrated inthe previous iigures.

. Referring to `the drawings, ille strurtnre livre shown comprises a rectangular tank that :is preferably constructed from lire steel plates.constituting thev four sides and the A'bottoni Athereof, suitable-angle irons being -located at. all abutting edges and` also al .thetop edges for lending` ruggedness and rigidity to the entire structure.

y Inasinucli as .the r'particularl construction of the electrolyte-container or tank is not relevant to the vpresentinvention, no further description thereot is deemed necessary.

lNithin the tank l, aplurality of sets of (2e-operating CTI electrodes 2, corresponding to the respective phases ot the secondary winding of the induction motor or other apparatus to be regulated, are located, each set of electrodes including' a lower stationary electrode 3 and an upper movable electrode l.

A torque motor 5, of a familiar type, is located above and to one side ot the tank l for the purpose ot operating` the movable electrodes An adjustable counterweight device 6 is attached to the operating member ot' the torque motor 5, as subsequently described in detail.

For the purpose ot suitably cooling the body ol electrolyte within the tank l, a pair ot` cooling tanks 7, shown in detail in Figs. al: and 5, extend longitudinally oli the tank l, as hereinafter more fully set `forth.

Surrounding each pair ot co-operatine` stationary and movable electrodes 3 and 411, respectively, is a cylindrical insulatin member 10, preferably comprising a selected length ot earthenware pipe, such as the Yfamiliar sewer tile, each tile resting upon a base 1l of slate, or other suitable material, the three bases being` disposed in abutting` relation and together extending for nearly the full length ot the tank. In this way, the respective sets ot electrodes are suitably spaced and electrically separated from each other, although, since the body of electrolyte in the tank l is normally ot a height greater than that of the several sewer tiles, equal pressures obtain both within and without the cylindrical tiles, whereby loss and leakage ot electrolyte from within the same is automatically eliminated or compensated for under all conditions. Thus, the diliiculty that has been encountered in various rheostats of the prior art, wherein the cylindrical containing members were not surrounded by electrolyte, is completely obviated.

Each stationary electrode 8 comprises a bottom or working plate member, the two opposite sides of which are drilled -tor the reception of a pair ot metallic rods 12 that extend upwardly from the working member on opposite sides of the corresponding` movable electrode 4t, which is located in substantially vertical alinement with the working member ot the stationary electrode For the purpose ol. suitably supportingand insulating the stationary electrodes :trom the tank l, a plurality olf porcelain insulators 13, or the like, are suspemlcd, by means ot small plates or sheets ll, ol n'ietal, which are suitably secured to a pair of chain nel irons 15 that rest upon upper edges of the tank and extend for the 'tull length thereof with respect to the longest dimension of the tank. The rods l2 terminate above the insulators 1? in suitable terminal or connecting members 1G, which may be electrically secured, in any suitable manner,

to the terminals of the induction motor or any other machine to be regulated.

Each movable electrode il is preferably ot the type set forth and claimed in Patent No, 1,2%Sfl95, issued to Geo. XV. Huey on Dec. l, 1917, and assigned to the litcstinghouse Electric & Manufacturing Company. ln general, the movable electrode comprises a plurality ot concentric rings that are supported by two cross bars extending at right angles, as best shown in lt will be understood, however, that any other suitable type of movable electrode may be employed in lieu oit that herein illustrated.

A. rod is secured centrally ot each movable electrode l and extends upwardly to an angle iron 2l that runs longitudinally ot the tank iter the purpose, o t supporting the three movable electrodes that are lot-ated therein. At points intermediate the respectivc pairs oit rods 20, a plurality ol eye bolts 22 are attached to the angle iron 2l. ly means ot suitable strain insulators '23, the eye bolts 22 are respectively connected to ropes or cables 24e that are adapted to vrind and unwind over a sheave-like end portion 25 out the one or the other 01"' two operating levers 2G that are actuated by means ol the torque motor 5.

The torque motor 5 is mounted to one side of, and above, the tank l, resting upon a suitable platform 30, constructed from angle irons or the like that are suitably secured to a plurality of plate members which rest upon, and are attached to, one pair ol the channel irons l5.

ln accordance with custon'iary practice, ach lever arm QG is rigidly mounted upon the operating shaft 27 ot the torque motor 5, and the end of each operating lever opposite to the end that supports the movable electrode is provided with a second sheave-like member 32 't'or guiding a rope or cable that is attached to the upper end ot the counterweight (i. rllhe counterweight G comprises a suitable number ot' relatively heavy disks or weight members 3ft that are permanently attached to a suitable ropc or cable. Ylelow the main counterweight members l-/I are suspended a plurality oli' spaced counterweight members S5, oi.l smaller dimensions, and which are attached to a rope or other flexible member i313. For the purpose o'l" suitably guiding the vertical. movements ol [he several counteru weights, a guide member Il?, constructed trom angle irons or the like, is provided, beingl suitably located near, and secured te, the platform 30 oi the torque motor IS. Below the illustrated position otl the last counteiavcight member is disposed a shelt or ledge 38 ttor a purpose to be set forth.

A plurality ot adjustable stop meml irs and 40 are attached to opposite sides ot the platform 30, being employed for the tlf) usual purpose ot' limiting` the rocking movements of the levers 26]' The cooliiig tanks'?v severally*comprise loiigitudinally#extending side plates 45 and 46 that are Welded orotherwise suitablyV secured to vertical end platesl'andfaI bot-4 tom plate 4S, the proportion otparts being" such thatV a relativelyA long and* deepfbiucfV narrow tank or-trough, open at tlie"top,is provided.

For'the"purposeoti supporting eaclr ottlie cooling tanks iiiv` position` witlii=ii'--'tlie inaiirtank l, a plurality of chaiin'eliirousf lower face-ot eaelicooling tank, as clearlyY illustrated iiifFig. 4i :In additioin a plu#- rality ot angle-iron*sections v5l exteiidlat* eially oit each coolingtz'inkon--then outer siciethercotand are adapted torest upon the= upper 'edges `ottlie corresponding sides o't the mainvl tank xl.

A plurality of short-pipesectionsl 52" pierce each ot tlieeoolingtanks, being suitably welded to `Jthe side'meinbei's 'tliereo't-f ln this \vay,' the coolingy medium that "cir-- eulates through eaclr of the-tanks -7 is adaptied to diiectlyiconvey away or dissipate the-f heat that is^producedinv the lelectrolyte reason of the intiinatecontact thereof Awith the kvarious pipe sections y525 I as well: as 'with the 'taeesproperot tliecoolingtanks Forthepuipose of admitting aA cooling fluid or other mediumtoveaelil'ot'tlielcoolingY tanks,` inlet pipes oi' vconduits fandmt are'vv 35"`provided near .the opposite? eiidsf taiiks being Aconnected `theretoby nieaiis-ot distributiiigoibranch pipesafeach' ot' which is provided 'witlra suitablemanuallfy operable valve 56. Each otl'ie pipes runs downwardly insidefoneot- 'the cooling tanks Y7 near oneeiidfplate 47 thereotf'aud is bent to also runv along tlie base vorubotteim plate 4:8. Eachpipeiteiniinates *in* a caplorI closure 57 near the vmiddle-`portion "of they For the purposewof "elile'ct'ing* an adequate circulation 'or tlie-A cooling me; diuiii, the horizontal' portion-ofeach pipe A55'A is provided with "aplur'alitygotsmall `holes oi' pertorationstl, as villi'istrate'd/"inFig 5.'

Near the top of each cooling tank 7 ou cooling tank.

the outer? iace tliei'eol/'a* relatively large outlet pipe 59 is provided whereby thelieated liquid, as it rises `tothe top ot the cooling` tank, is conveyedv away through* the pipel 5U to be discharged inf any suitableiiiaiinen lt will be evideiit'that any -desired-sourcef ot I'luid pressure inav be connected-tothe inlet pipes and i' .sincenofdirectcontact with the electrolyte in the mainY tank al occurs, but a continuousv circulation or flowA of the cooluig :medinini-rom the botto'inol eachcoolingl tank l#to theltopl thereof takes' place Wliereby'tlie' suri-oundiiig body of elec# trolyte is effectively cooled Each cooling tank 7 is thus readnyportable7 which is oi great advantage in asseiiibling the slip regulator, and also inthe case` of repairs or? replacements.

Tlieopei'ationot my slip regulator may 'be set forth as follows: After connection of the variousterminal members i6 to the terminalineinbers of the induction motor or other device to be regulated, ymoveineiitoty faetthat, although eachv setfof stationai-','- and co-operating movable/contact l members-3 is -siii'r'ouiided by the earthenware barrels or tile nienibeis l() 'for provid-ing the most effective operation ot thel rheostat, neverrtheless the rlieostat will operate'feveii ii" one ot the tile n'ieinbers is brokei'roryin the extreme ease,'if the two outeritile iiieiiibeis are both broken. operation is possible in slipA regulators einbodying"separate4 chambersor conipaitiiientstor the-respective sets' ot electrodes, which compartments are ii'ot submerged in a body or electrolyte.

The actionfot the set vof counteivf'eiglits'f also constitutes-a .'aluable feature ot my As the elf-ectroldes*v are separated by tlie'ae'tion of tlietorque-motor, the v various counterweiolits1 are loweredI`4 un til: the lowest weiglitjo rests-upon tliefslielf or ledge 38.V` ly reasoirof tlie-tlexibil'ity lot tlierope oi'fcable 36,1the effective weight vot additional weiglitaneinbers 35 are reiidere'l ineffective by reason ot piling up on tlie shelfV 38py In ease the electrodes are caused to" approach each other, i the opposite action,

thatis, a gradua'lf'increase of the e'tective weight ot the counter-poise G, is., oit course, produced- The`advant-agesI oit this consti-uclioiruiay besettoi'tlr as tollows: llllienever an iii-l ei'ease iii load upon the motor being regu- 'lated occurs, the action oit the torque'fiiiotoi causes the electrodes to be separated.y whereby the gradual decrease inV the effective weight o'tl tlie'counterlioise' 6 takes-place, as previouslydescribed.- lii'thisway.,A a greater electrical load is imposed `upon the torque motor, whereby the action thereof is damped;

or retarded to pi'eventthe torque motor troniv oversliooting the desired' stabilizing posr' tion, especially in the event ot a siuildenoin-A crease in load upon the main motor.

lt is evident that nosueli yies-y tlie eounterpoise 6 is reduced to tlieiextent ot' the Weight of? the ymember in quefeti'oir -Upoir further separation ot theelectrodes and consequent Ylowering ot tlie-counterpoise,

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(in the other hand, the gradual inri"ase in the eitl'ective weight ot the counterpoise as the electrodes are caused to approach each other, allows the torque motor to increase in speed, tb ellecting a more rapid approach oi the pairs of electrode members and :facilitating the return to normal speed ot the main motor being regulated. In other Words, the torque motor is adapted to more quickly effect an approach olj the electrodes to reduce the secondary resistance in the mainmotor circuiti and. consequently, more quickly return power into the fly-Wheel ot the mainmotor set, so *l wat the load is taken off the ily Wheel in case of heavy peaks and the tendency ot the motor to carry loads which the fly wheel should carry is reduced.

l have thus produced a liquid rlieostat or slip regulator that is rugged in construction, ellicient in operation, by reason o't the elimination of the electrolyte losses and leakage, that is elii'ectively cooled by means ot portable cooling tanl-:s and that automatically Afunctions to reduce the speed ot separation of the co-operating electrodes and increase the speed of approach thereof 'tor the purposes set forth.

I do not Wish to be restricted to the specilic details ot construction or arrangement of parts herein set forth, as various modifications tliereot' may be effected Without departing from the spirit and scope ol my invention. l desire7 therefore, that only such limitations shall be imposed as are indicated by the appended claims.

l claim as my invention l. A liquid rheostat eml'iodyinga movable electrode and a` eti-operating stationary electrode comprising a Working member located opposite said movable electrode and a plurality of supporting members disposed on opposite sides olf the movable electrode.

2. A liquid rheostat embodying a movably suspended electrode and a cti-operating stationary electrode comprising a Working member located in substantially vertical alinement with said movable electrode and a plurality ot suspending members extending on opposite sides oil the movable electrode.

2"). liquid rheostat embodying a movably suspended electrode and a co-ope ating slalionary e eetrode comprising a working member locatedv directly belouY said movable electrode and a plurality ol' suspending rods extending up\\=ardly ou opposite sides olf the movable elect rode.

l. A liquid rheoslat embodying a movable elect-rode and a copiierating stationary electrode comprising a metallic member located. opposite said movable electrode.y a pluralita7 oi" 'metallic supporting members disposed on opposite sides olf the movable electrode, and insulating coveringmeans Ytor said supportn ing members.

5. liquid rlicostai'y embfalying a moral-ily suspended electrode and a co-opcrating sationa-ry electrode comprising a metallic member located inv substantially vertical aline-- ment with said movable electrode` a plurality et suspending members eidttuiding on opposite sides ot the movable electrode. and unitary insulating means surromuling each oli' said suspending men'lbers.

G. A liquid rheostat en'ibodying a mov ably suspended electrode and a cio-operating stationary electrode comprising a` metallic member located directly below said n'iovable electrode, a plurality ol suspending rods ex tending upwardly on opposite sides ot the movable electrode, and a plurality ot tubular insulating members severally enclosing said suspending rods. i

7. liquid rheostat embodying able electrode and a co-opcrating stationary electrode comprising a metallic member located opposite said movable electrode. a plurality ot metallic supporting members disposed, on opposite sides oft the movable electrode, and means for restricting the electric current path substantially to the space between said movable electrode and the first-named metallic member.

8. A liquid rheostat embodying a movably suspended electrode and a co-operat ing stationary electrode con'iprising a metallic member located in substantially vertical alinement with said movable electrode. a plurality ot suspending members extending on opposite sides oit the movable electrode, and means Yfor restrictingv the electric current path substantially to the space between said movable electrode and said metallic member.

9. A liquid rheostatembodying a movably suspended electrode and a co-operatinfr sationary electrode comprising a metallic member located directly below said movable electrode, a plurality ot suspending rods extending upwardly on opposite sides ot the movable electrode.r and insulating means for restrictingthe electric current path substantially to the space betvfeeu said movable electrode and said metallic member.

l0. A liquid rheostat con'iprisiirg a taal@ aA plurality o'l. stationary electr-ale members disposed therein, a simporting member erflending along the, top oll ,said laid; near edge thereof. and means l'or suspendiagsaid electrode members trom said supporting member.

ll. A liquid rhoostat comprising a lanlf. a plurality oli stationary electrode meml disposed therein.` a plurality ol supi, )rtina' members extending along the top ot said tank near opposite edges thereot7 and means :tor suspending said electrode members trom each olf said supporting members.

12. A liquid rheostat comprising a tanl,

lil)

a plurality oi' stationary electrode lmembers disposed-therein, a. supporti-ng member eX- tendingalougftlie top ot' saidftanknear-one ede'e tliereofli, a plurality ot plate members extending,l at substantially right angles and secured to said srqiporting,l members, ai .Jlal plural ity f V'of insulatingl members rseverally supported by saidv plate'finembersand1 in members.

13. A liquid rlieestat comprisinga tank, a. plurality ot stationary electrode members disposed therein, a. plurality-'ot supporting" members extending;4 along the top ot said tank near opposite edges'thereof, a plu'-r ralityot plate-members, oppositely disposed in pairs, extending at substantially rightangles andseCured to the one or the lother ot said support-ing:members, and `a plurality of "insulating members severally supportedby said plate members and in turn acting in pairs to support the respective electrode members.

la. A liquid rheostat comprising a tank,

av plurality ol stationary electrodes disposed therein, and` :means comprising` a plurality `ot' closed `barriersY surrounding the"l respective electrodes and i themselves: ,inimersed in the liquid-within. saldi tank.

l5. i liquid rheostat,comprising a: tank.,- a pluralityot sta-tionary electrodes disposedtherein, a plurality ot movablel electrodes-'located in substantially vertical alinement with the respective station-ary electrodes,-

and aclosed barrier of insulating materialy surrounding each pair of (3o-operating electrodes 'and itsel'lf'immersed in the liquid Within said tank.

16. A liquid rheostat comprising a tank, a plurality oi' stationary electrodes disposed therein, a. plurality ot' movable electrodes located in substantially vertical alinement with the respective stationary elect-redes, a cylindrical eartlienivare barrier enclosing` each pair et eo-oqiierating electrodes and itself immersed in the liquid within said tank, and a closure oit insulating material 'lor the lower end ot each barrier resting upon the floor ot said tank.

17 A liquid rheostat comprising` a. movable electrode, means for operating` said electrode, anda counteriveight tor said elec-l ot saidcounterweight while operating in a single medium in accordanceavidi-the posi tioirtliereo'f.

20; A liquid rlieostat comprisingamove able electrode, means for operating said el'ectrode, a counterweig'ht for"saidfelectrode turnk severally* suppo'rtmg;` `said Eelectrode comprisinga pluralityoi iveightssuspended and spaced apart on a` Iflexible member, and-'a vstationary shelf for successively arresting the; downward `progress of said Weight.

trode, a counteriveight Yfor said electrode comprising a plurality of weights suspended f` and spaced apart on a ieXible-nien'iber, a

vertical guide member :tor said weights, and' a stationary slielt upon Whiclrsaid ufeights may successively restas the electro'de'moves Within predetermined limits.

22. The combination With a movable mem` ber `and actuating means therefor, of a counterweiglitl for' said movablei member, the

4eiiectivey Weight of which v'vhi'le operating` in a single' medium is dependent upon the posi` tion or" said movable member.'

23. Thecombination"with a movable mem-y ber and actuating means therefor, ot a counteriveight for saidfmova'ble member, the effective Weight'of which While 'operating in a singleniediuinrespectively increases and decreases as it is moved upwardly and ldovvn'- Wardly;

24. A liquid rheostat comprising va mov-v able Aelectrode'member, vtorque imotor for actuating'- "said Amovablemember, and counterweight for said movable member automatically operative to retard the movement of the movable member .in one direction and expedite it in the other direction.

25. A liquid rheostat comprising` a stationary and a movable electrode member, a torque inotoi for actuatingl said movable member, and a counterweiglit automatically operative to rctardthe separat-ion and expedite the approach oli the movable electrode member with respect to the stationary electrode member.

2G. A liquid rlieostat comprising a stationary and a movable electrode member, a torque motor for actuating said movable member, and a counterweiglit automatically operative to increase or decrease the load on said torque motor in accordance with the direction of operation thereof.

' 27.A liquid rheostat comprisingva stationary and a movable electrode member, a torque motor for actuating said movable member, and a counteriveight automatically operative to increase the load on said torque motor when the electrodes are separating and to decrease such load when the electrodes are coming` together.

2S. An electrode for liquid rlieostats coniprising a Working memberI extending in a substantially horizontal plane, a plurality of substantially vertical metallic supporting members secured to opposite sides ot.' said working member, and unitary .insulating means enclosing the respective supporting members.

29. A liquid rheostat comprising a container ior electrolyte and a portable cool ing tank suspended from an upper edge of said container.

30. A liquid rheostat comprising a container for electrolyte, a portable cooling tank supported by said container, and means Yfor circulating a cooling medium through said tank.

3l. A liquid rheostat cmnprising a container for electrolyte, and a relatively ila-t cooling tank suspended therewithin and having a plurality of passages therethrough tor ellecting intimate contact with said electrolyte.

3Q. A liquid rheostat comprising a container tor electrolyte, and a relatively deep and nari-onT trough suspended therewithin and having a plurality of passages extending therethrough in the direction o1" the narrow dimension for effecting intimate contact with said electrolyte.

A liquid rheostat comprising a container for electrolyte, a relatively deep and narrow trough suspended therewithin, and a perforated pipe extending near the bottom of said trough for circulating -a cooling medium upwardly therethrough.

A liquid rheostat comprising a container for electrolyteJ a pair of cooling tanks suspended from opposite sides of said container, and pipe connections `for supplying a cooling medium to corresponding parts ot said tank, and means lor independently regulating the l'low of said medium to said tanks.

35. A liquid rheostat comprising a container `itor electrolyte, a pair ot' relatively flat cooling tanks severally having a plurality of projections on one side for resting upon opposite upper edges of said container, and means for supplying a cooling medium to the corresponding ends of said tanks.

36. A liquid rheostat comprising a container for electrolyte, a pair ot relatively deep and narronv troughs provided with projections in the direction of the narrow dimension lor resting upon opposite upper edges of said container, and cooling fluid conveying means connecting the corresponding ends ot said troughs.

3'?. A liquid rheostat comprising a container for electrolyte, a pair ot relatively deep and narrow troughs provided with projections in the direction of the narrow dimension for resting upon opposite upper edges of said container, pipe members for connecting corresponding ends ot said tanks, and a plurality of perforated pipes extend ing Afrom each side along the bottom of each trough for circulating a cooling medium npwardly therethrough.

In testimony whereof, I have hereunto subscribed my name this 7th day oit' August7 w22.

HARRY A. LEV/'IS 

